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Wi-Fi Alliance introduces Wi-Fi 6

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Re: Wi-Fi Alliance introduces Wi-Fi 6

#91

Post by mrb »

ricardobeat wrote: post #53
mrb wrote: post #46

Really good whitepaper on WiFi 6 (802.11ax): https://www.cisco.com/c/dam/en/us/products/collateral/wirele... Also: http://www.ni.com/white-paper/53150/en/ Main differences with 802.11ac: - denser subcarriers (or "tones") spacing; they are spaced by 78.125 kHz instead of 312.5 kHz, for example a 80 MHz channel now allows 980 data subcarriers, up from 234. That's a 4.19× improvement (4× higher density doesn't translate…

Due to the increased efficiency, the speed increase is supposed to be much higher. At CES they showed up to 11Gbits: https://www.zdnet.com/article/d-link-asus-tout-802-11ax-wi-f...

Well this D-Link router shown at CES is "tri-band" (a misnomer, it should be called "tri-channel") so "11 Gbit/s" is just the sum of the maximum data rate achievable in 3 different channels (one channel in the 2.4 GHz band, plus two channels in the 5 GHz band), where each channels is as wide as possible (40 MHz at 2.4 GHz, and 160 MHz at 5 GHz), and where each channels uses 4 MIMO streams (ie. 4 antennas transmitting concurrently.) For comparison, the number I quoted in my parent post is just for 1 channel at 80 MHz with 1 MIMO stream.

D-Link can claim "11 Gbit/s" because:

- first channel at 2.4 GHz is 40 MHz wide (468 data subcarriers) where 802.11ax can operate at 286.8 Mbit/s, multiplied by 4 streams = 1147 Mbit/s

- second channel at 5 GHz is 160 MHz wide (1960 data subcarriers) where 802.11ax can operate at 1201.0 Mbit/s, multiplied by 4 streams = 4804 Mbit/s

- third channel also provides 4804 Mbit/s

1147 + 4804 + 4804 = 10755 Mbit/s which D-Link's marketing team rounds to "11 Gbit/s." It goes without saying that a typical client WiFi device (phone, laptop) will never reach 11 Gbit/s. For starters it will only use 1 of the 3 channels (4804 Mbit/s maximum) and most devices are 2×2 thus capable of 2 streams (2402 Mbit/s maximum.) Even if they are 3×3 you'd be lucky in real-world conditions to get about one and a half times or twice the bandwidth of one stream.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#92

Post by forapurpose »

kalleboo wrote: post #42
forapurpose wrote: post #33

Earlier quoted context omitted.

> The larger problem with the 2.4 GHz ISM band is ... only one station being able to transmit at a time per channel Is there any Wifi tech for which that isn't true, sans beam-shaping and other tech that effectively puts stations on different physical networks? How do 5 GHz technologies handle multiple simultaneous broadcasts on the same channel? How will 802.11ax do it? Signal processing? My impression, based on onl…

Maybe this? https://en.wikipedia.org/wiki/IEEE_802.11ax#Technical_improv... > Spatial frequency reuse > Coloring enables devices to differentiate transmissions in their own network from transmissions in neighboring networks. > Adaptive Power and Sensitivity Thresholds allows dynamically adjusting transmit power and signal detection threshold to increase spatial reuse. > Without spatial reuse capabilities devices refu…

That makes good sense to me, but it's still basically keeping stations on separate networks - it's managing the networks' transmission power carefully so they can run in closer proximity.

Still I don't know a solution to concurrent broadcasts on the same network, as the GGP comment seemed to imply.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#93

Post by bdamm »

gammateam wrote: post #79
mrb wrote: post #46

Really good whitepaper on WiFi 6 (802.11ax): https://www.cisco.com/c/dam/en/us/products/collateral/wirele... Also: http://www.ni.com/white-paper/53150/en/ Main differences with 802.11ac: - denser subcarriers (or "tones") spacing; they are spaced by 78.125 kHz instead of 312.5 kHz, for example a 80 MHz channel now allows 980 data subcarriers, up from 234. That's a 4.19× improvement (4× higher density doesn't translate…

all I want to know is the maximum speed file transfer I can expect? with unlimited pipes from my ISP, and a fat 802.11ax router, what can I theoretically expect on speedtest.net I feel like your analysis neglected using multiple bands or channels or whatevers at once, and how the routers all can do double, tri quad bands already and might do more for this technology so we talking 3 Gbit/s?

How many other users are in your local area, and their use of the common medium, also matters. So it's hard to really state what boost you can expect in your own home. My read on this new standard is that it's built with conflict reduction in mind.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#94

Post by bjoli »

sargun wrote: post #85

It’s kinda a bummer to see 802.11ad being ignored. I use 802.11ad for game streaming in my house, and it’s great. It’s also great for the “access point per room” story, if there was a mechanism to have cheaper APs and do hand off.

I suspect the numbering will only be used for more or less backwards compatible standards. I doubt they will break compatibility with N anytime soon.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#95

Post by SEMW »

derefr wrote: post #58
chipperyman573 wrote: post #45

Earlier quoted context omitted.

AC only supports 5gz, which has significantly worse range and is impacted much more by walls or other solid objects. But if there aren't a problem it's generally better

Those limitations are a good thing: they reduce interference from neighbouring apartments/offices, and even interference between overlapping cells of a mesh network or a base station and its extenders. In practice, this means that the extenders can extend longer, so something like a convention center or work-sharing space can use approximately the same number of base stations it did before. The only problem is that y…

> imagine a light that can manage to penetrate a bathroom wall, and tell me you don’t think it’s maybe a bit too powerful for consumer use ;)

Visible light has a wavelength of a few hundred nanometers; wifi is around 10 centimeters. Material penetrability varies enormously between different wavelengths (and between materials). Harm to humans also various enormously, and in a way very different from penetrability (for example, some wavelengths of UVC are very harmful to human skin but can be almost completely blocked by a thin sheet of clear glass). Equating penetrability with either 'power' or harmfulness is not a useful intuition.

(incidentally, an incandescent light bulb emits on a blackbody spectrum, so some very small proportion of the energy it uses will be emitted at e.g. radio wave frequencies, which will certainly penetrate the bathroom wall)

Re: Wi-Fi Alliance introduces Wi-Fi 6

#96

Post by zamadatix »

rsynnott wrote: post #90
zamadatix wrote: post #61

Earlier quoted context omitted.

That's just the marketing, AC would have been 7 gbit/s if measured in the same ludicrous 8x8 160 MHz setup (though technically AC only specifies up to 4x4 it doesn't matter, clients are almost exclusively 2x2, even high end laptops). Even in a full greenfield ax deployment it'll be a rare sight to see your phy rate pop above 1 gbit/s half duplex as a client. Like the parent comment said the actual felt speed gains in…

MacBook Pros have had 3x3 for a while now (except for the non-touchbar 13” post-2016, which is really more of a MacBook Air internally anyway).

Yep, it's about the one client I ever see be 3x3. They use a specially customized version of the 2014 BCM943602 to do it. Don't think I've ever seen a 4x4 client pop into our logs that wasn't an AP to AP bridge but I know there are a handful of adapters made which support it.

Interestingly Intel gave up on making 3x3 cards a couple of years ago but will sell you a 160 MHz 2x2 ¯\_(ツ)_/¯

Re: Wi-Fi Alliance introduces Wi-Fi 6

#97

Post by ksec »

WiFi 6, or 802.11ax, has been in development for sometime and faces lots of difficulties and controversies.

First it was discovered all the major companies were working behind close door forming a group called Densi-Fi, trying to super speed the spec, or more like neglecting all the issues around it and push forward the time to market. This has been discover by some other IEEE members, and the problem has since been "resolved". The Density-Fi section in 802.11ax has since be deleted from Wiki, despite many attempts to bring it back. The 802.11ax committees continue to push forward and correct me if I am wrong, are there any other IEEE spec that failed to pass in all of its Draft? Draft 1.0, 2.0 and 3.0 for 802.11ax all failed to pass the vote. With Draft 4.0 being pushed and forcibly passed, while all the comments ( ~2300 of it ) being the same and unresolved as Draft 3.0. Much like 802.11ac there will be Wave 1 and Wave 2. Wave 1 does not include Uplink MU-MIMO, 80+80Mhz Channels and some other things I don't remember on top of my head.

I am not sure what to make of this. Because it reads to me as a giant pile of mess and I don't want to be the guinea pig for this new spec.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#98

Post by WorldMaker »

Dylan16807 wrote: post #88
WorldMaker wrote: post #49

Earlier quoted context omitted.

I think 802.11-1997 works as 0 in this case. The implication from the Wi-Fi Alliance seems to be they are counting consumer hardware generations, and there doesn't seem to have been much consumer hardware that was directly 802.11-1997 (it took b to get consumer adoption). Which is why the order I've heard that makes the most sense is 1 (b), 2 (a), 3 (g), because that was roughly the consumer hardwave waves, with the…

a and b were specced at the same time though, so it's really weird to look at a+b+g as anything other than two generations.

That's certainly a fair viewpoint (and reflected together in the spec version 802.11-1999), but the interesting thing about this rebrand is the Wi-Fi Alliance taking a step back, realizing that the individual specs don't matter to consumers and as a consumer brand trying to break away from just using the spec names/versions.

From that perspective A, B, and G were all sold as three separate things to consumers, so it makes sense to count all three.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#99

Post by DesertBattery »

mrb wrote: post #50
chipperyman573 wrote: post #45

Earlier quoted context omitted.

AC only supports 5gz, which has significantly worse range and is impacted much more by walls or other solid objects. But if there aren't a problem it's generally better

"AC only supports 5gz." That's not an accurate statement. "802.11ac" denotes a set of features, and many of them apply to and benefit the 2.4 GHz band. For example 256QAM encoding boosts the max data rate by 20 or 33% on this band for, respectively, 20 and 40 MHz channels.

> 802.11ac is a 5-GHz-only technology

https://www.cisco.com/c/dam/en/us/products/collateral/wirele...

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